Global Search List of Values- Last Name Behavior

Hi Oracle Experts,
We are facing an issue with Global Search in Oracle Cloud HCM related to searching by last name in Global Search.
Currently, searching by first name alone works as expected.
For example:

When I search for “John”, all relevant results are returned correctly. When I search with Person number, results are appearing correctly. When I search with full first name and last name, results are appearing fine.

However, the issue occurs when we try to narrow the search using partial last names:

When searching for “John C”, the results returned include names like John Szzz, John Raaa, etc.